.box-sizing-example {
  background: red;
  padding: 20px;
  border: 10px solid green;
  margin: 20px;
  width: 200px;
}

#content-box {
  -moz-box-sizing: content-box;
  -webkit-box-sizing: content-box;
  box-sizing: content-box;
}

#border-box {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.test {
  background: red;
  padding: 5px;
}
